Medically-insignificant
Guides
Cheiracanthium mildei
Northern Yellow Sac Spider, Long-legged Sac Spider
Cheiracanthium mildei is a medium-sized spider native to Europe and North Africa, introduced to North America and parts of South America. Adults measure 7–10 mm in body length with pale green or tan coloration, darker palpi and chelicerae, and characteristically long front legs up to twice the length of others. It constructs silken retreats rather than capture webs, hunting actively at night. The species is frequently encountered in human dwellings, particularly in northern regions of its introduced range, and has been documented to bite humans with generally mild effects.
Dysdera
woodlouse hunter, sowbug killer, slater-eating spider, woodlouse spider, pillbug hunter
Dysdera is a genus of spiders in the family Dysderidae, first described by Pierre André Latreille in 1804. The genus originated from Central Asia to Central Europe and has since spread globally through human commerce. Members are specialized predators of woodlice (terrestrial isopods), using enlarged chelicerae and long fangs to pierce their armored prey. The genus exhibits remarkable adaptive radiation, particularly on oceanic islands—most notably the Canary Islands, where 48 endemic species occur. Dysdera crocata, the cosmopolitan woodlouse hunter, is the only widespread species outside its native range and the sole representative in North America.
Dysdera crocata
Woodlouse Spider, Woodlouse Hunter, Sowbug Hunter, Sowbug Killer, Pillbug Hunter, Slater Spider
Dysdera crocata is a specialized spider predator native to the Mediterranean region of Europe that has become established worldwide through human commerce. It is the only representative of the family Dysderidae in North America. Despite its formidable appearance—featuring disproportionately large chelicerae and long fangs—it poses no significant danger to humans. The species has been the subject of recurring internet hoaxes falsely claiming it is a new, deadly spider. It is primarily nocturnal and strongly associated with human-modified environments, particularly where its woodlouse prey abounds.